Air conditioning systems

Abstract

An air conditioning system includes a refrigerant circuit. The refrigerant circuit includes a compressor for receiving a refrigerant gas and for compressing the refrigerant gas, and a condenser for condensing a portion of the compressed refrigerant gas into a liquid refrigerant. The refrigerant circuit also includes an expansion valve for reducing a pressure of the condensed liquid refrigerant, and an evaporator for evaporating the condensed liquid refrigerant. Moreover, the compressor is driven by an electric motor which controls a rotational speed of the compressor via an inverter, and a temperature of the inverter is decreased by the refrigerant circuit. The system also includes an electric circuit for determining whether a temperature of the inverter is greater than a first predetermined temperature, and an electric circuit for controlling a rotational speed of the compressor. Specifically, when the temperature of the inverter is greater than the first predetermined temperature, the electric circuit decreases the rotational speed of the compressor.

What is claimed is:  
     
       1. An air conditioning system comprising: 
       a refrigerant circuit, wherein said refrigerant circuit comprises:  
       a compressor for receiving a refrigerant gas and for compressing said refrigerant gas;  
       a condenser for condensing at least a portion of said compressed refrigerant gas into a liquid refrigerant;  
       an expansion valve for reducing a pressure of said condensed liquid refrigerant; and  
       an evaporator for evaporating said condensed liquid refrigerant, wherein said compressor is driven by an electric motor and said electric motor controls a rotational speed of said compressor by an inverter, wherein a temperature of said inverter is decreased by said evaporated refrigerant;  
       means for determining whether a temperature of said inverter is greater than a first predetermined temperature; and  
       means for controlling a rotational speed of said compressor, such that when said temperature of said inverter is greater than said first predetermined temperature, said means for controlling said rotational speed of said compressor decreases said rotational speed of said compressor.  
     
     
       2. The air conditioning system of  claim 1 , wherein said means for controlling said rotational speed of said compressor comprises a first electric circuit and said means for determining comprises a second electric circuit. 
     
     
       3. The air conditioning system of  claim 1 , further comprising means for stopping a rotation of said compressor when said temperature of said inverter is greater than a second predetermined temperature, wherein said second predetermined temperature is greater than said first predetermined temperature. 
     
     
       4. The air conditioning system of  claim 3 , wherein said means for stopping comprises an electric circuit. 
     
     
       5. The air conditioning system of  claim 1 , wherein when after an activation of said compressor said temperature of said inverter is greater than said first predetermined temperature, said means for controlling substantially maintains said rotational speed of said compressor at an activation rotational speed, wherein rotating said compressor at said activation rotational speed decreases said temperature of said inverter below said first predetermined temperature. 
     
     
       6. The air conditioning system of  claim 1 , further comprising means for detecting a suction pressure of said compressor, wherein when a calculated temperature of said inverter is greater than a third predetermined temperature, said means for controlling said rotational speed of said compressor decreases said rotational speed of said compressor. 
     
     
       7. The air conditioning system of  claim 6 , wherein said means for detecting comprises a pressure sensor. 
     
     
       8. The air conditioning system of  claim 1 , further comprising means for controlling a volume of air passing through said evaporator, wherein when said temperature of said inverter is greater than said first predetermined temperature, said means for controlling said volume of air passing through said evaporator decreases said volume of air passing through said evaporator. 
     
     
       9. The air conditioning system of  claim 8 , wherein said evaporator comprises an evaporator fan and said means for controlling said volume of air comprises a first governor, wherein when said first governor reduces a rotational speed of said evaporator fan said volume of air passing through said evaporator decreases. 
     
     
       10. The air conditioning system of  claim 1 , further comprising means for adjusting a size of an opening of said expansion valve, wherein when said temperature of said inverter is greater than said first predetermined temperature, said means for adjusting said size of said opening increases said size of said opening. 
     
     
       11. The air conditioning system of  claim 10 , wherein said means for adjusting comprises a governor. 
     
     
       12. The air conditioning system of  claim 1 , wherein said condenser comprises a condenser fan, further comprising means for controlling a rotational speed of said condenser fan, wherein when said temperature of said inverter is greater than said first predetermined temperature, said means for controlling said rotational speed of said condenser fan increases said rotational speed of said condenser fan. 
     
     
       13. The air conditioning system of  claim 12 , wherein said means for controlling said rotational speed of said condenser fan comprises a governor. 
     
     
       14. An air conditioning system comprising: 
       a refrigerant circuit, wherein said refrigerant circuit comprises:  
       a compressor for receiving a refrigerant gas and for compressing said refrigerant gas;  
       a condenser for condensing at least a portion of said compressed refrigerant gas into a liquid refrigerant;  
       an expansion valve for reducing a pressure of said condensed liquid refrigerant; and  
       an evaporator for evaporating said condensed liquid refrigerant, wherein said compressor is driven by an electric motor and said electric motor controls a rotational speed of said compressor by an inverter, wherein a temperature of said inverter is decreased by said evaporated refrigerant and said inverter is formed integrally with said compressor;  
       means for determining whether a temperature of said inverter is greater than a first predetermined temperature; and  
       means for controlling a rotational speed of said compressor, such that when said temperature of said inverter is greater than said first predetermined temperature, said means for controlling said rotational speed of said compressor decreases said rotational speed of said compressor.  
     
     
       15. The air conditioning system of  claim 14 , further comprising means for stopping a rotation of said compressor when said temperature of said inverter is greater than a second predetermined temperature, wherein said second predetermined temperature is greater than said first predetermined temperature. 
     
     
       16. The air conditioning system of  claim 14 , wherein when after an activation of said compressor said temperature of said inverter is greater than said first predetermined temperature, said means for controlling substantially maintains said rotational speed of said compressor at an activation rotational speed, wherein rotating said compressor at said activation rotational speed decreases said temperature of said inverter below said first predetermined temperature. 
     
     
       17. The air conditioning system of  claim 14 , further comprising means for detecting a suction pressure of said compressor, wherein when a calculated temperature of said inverter is greater than a third predetermined temperature, said means for controlling said rotational speed of said compressor decreases said rotational speed of said compressor. 
     
     
       18. The air conditioning system of  claim 14 , further comprising means for controlling an volume of air passing through said evaporator, wherein when said temperature of said inverter is greater than said first predetermined temperature, said means for controlling said volume of air passing through said evaporator decreases said volume of air passing through said evaporator. 
     
     
       19. The air conditioning apparatus of  claim 14 , further comprising means for adjusting a size of an opening of said expansion valve, wherein when said temperature of said inverter is greater than said first predetermined temperature, said means for adjusting said size of said opening increases said size of said opening. 
     
     
       20. The air conditioning system of  claim 14 , wherein said condenser comprises a condenser fan, further comprising means for controlling a rotational speed of said condenser fan, wherein when said temperature of said inverter is greater than said first predetermined temperature, said means for controlling said rotational speed of said condenser fan increases said rotational speed of said condenser fan. 
     
     
       21. The air conditioning system of  claim 14 , wherein said means for stopping a rotation of said compressor when said temperature of said inverter is greater than said second predetermined temperature and said means for controlling a rotational speed of said compressor are formed integrally with said inverter. 
     
     
       22. A method of employing an air conditioning system comprising a compressor for receiving a refrigerant gas and for compressing said refrigerant gas, a condenser for condensing at least a portion of said compressed refrigerant gas into a liquid refrigerant, an expansion valve for reducing a pressure of said condensed liquid refrigerant, and an evaporator for evaporating said condensed liquid refrigerant, wherein said compressor is driven by an electric motor and said electric motor controls a rotational speed of said compressor by an inverter, comprising the steps of: 
       determining whether a temperature of said inverter is greater than a first predetermined temperature; and  
       decreasing a rotational speed of said compressor when said temperature of said inverter is greater than said first predetermined temperature.  
     
     
       23. The method of  claim 22 , further comprising the step of stopping a rotation of said compressor when said temperature of said inverter is greater than a second predetermined temperature, wherein said second predetermined temperature is greater than said first predetermined temperature. 
     
     
       24. The method of  claim 22 , further comprising the step of decreasing a volume of air passing through said evaporator when said temperature of said inverter is greater than said first predetermined temperature. 
     
     
       25. The method of  claim 22 , further comprising the step of increasing a size of an opening of said expansion valve when said temperature of said inverter is greater than said first predetermined temperature. 
     
     
       26. The method of  claim 22 , wherein said condenser comprises a condenser fan, further comprising the step of increasing a rotational speed of said condenser fan when said temperature of said inverter is greater than said first predetermined temperature.